Free 8.5- x 11-inch map of Colorado geology (front) along with Geo-Whizology (back). General, Geology, Publications February 28, 2008 The biggest, the best, the first, and the most diverse… We have a free 8.5- x 11-inch (pdf) geologic map of Colorado containing Geo-Whizology of Colorado on the reverse side. Of course, we’re a bit biased, but we think Colorado has magnificent geology and it is beautifully displayed for all to see. The state holds many…
Figure 3 -- This development in west Glenwood Springs constructed a rockfall impact wall above their townhomes to protect against both rockfall and mudslides (debris flows). Photo credit: Jon White for the CGS.|Figure 2 -- Several large rocks from the western wall of the Roaring Fork River in Glenwood Springs crashed into the houses below during the early morning causing significant damage Hazards July 6, 2005 Case Study: Rockfall – Glenwood Springs The town of Glenwood Springs in west-central Colorado lies at the confluence of the Roaring Fork and Colorado rivers. The town is tightly constrained by the steep river valleys so land-development pressure is causing residential growth to push into rockfall hazard areas. In West Glenwood, on the west side…
By August 2005 Hazards June 21, 2005 Case Study: Clear Creek Canyon rockslide Rockfalls and rock slides are common along transportation corridors in the Rocky Mountains. Clear Creek Canyon just west of Golden is one of the most active rockfall areas in Colorado. The canyon has been cut into Precambrian schists and gneisses by Clear Creek, one of the primary drainages in the…
Retaining wall settlement at the center of the image with the sorority houses in the background and the IM field in the foreground. Photo credit: T. C. Wait for the CGS.|The Rockwell clay mine area immediately south of the CSM campus along US 6 in 1977 before more recent reclamation as a golf course. The green area to the top left is part of the IM field where the subsidence occurred. Photo credit: Colorado Geological Survey.|DC resistivity survey crew from the engineering firm Zapata/Blackhawk laying out the multicore switch cables across the IM field area in 2008. Photo credit: T. C. Wait for the CGS.|Subsidence road damage near one of the sorority houses at CSM in August 2005. Photo credit: T. C. Wait for the CGS.|A drill-rig preparing boreholes for subsurface grouting under the IM field in August 2005. Photo credit: T. C. Wait for the CGS.|One of the several subsidence features in the IM field at the Colorado School of Mines in 2005. Photo credit: T. C. Wait for the CGS.|Figure from DC resistivity report from 2009 detailing some of the infrastructure Geology, Hazards April 26, 2005 Case Study: mine subsidence, CSM For decades, the west side of the Colorado School of Mines (CSM) main campus had subsidence issues related to historical mining activities. At one point, in the 1990s, one of the married student housing units in that area was so badly damaged that it was condemned. In the early…
Bohemian karst (Český kras) landscape formed in a limestone of Silurian and mainly Devonian age. The area hosts several international stratotype and parastratotype sections General March 4, 2005 Dr. Cílek on the Bohemian karst Dr. Cílek, the Director of the Czech Republic’s Academy of Sciences Institute of Geology delivers a fascinating talk about the Bohemian Karst region of the Czech Republic, around Beroun, that weaves the human historical, mystical, and mythological elements…
A large sinkhole opened in January 2005 at the Ironbridge Development and Golf Course Hazards January 17, 2005 Case Study: Roaring Fork sinkhole [ED: This report from January 17, 2005 was written by Jon White, (Senior Engineering Geologist, Emeritus). Lightly edited for dated references it highlights a hazardous geological regime in the central Colorado Rockies around the Roaring Fork River Corridor.] Last week, while on the Western Slope, I was informed by…
Avalanche debris in the runout zone taken from a helicopter on the morning after the avalanche occurred Hazards March 24, 2003 Case Study: Avalanche – Silver Plume On March 23, 2003, a large avalanche occurred about one mile west of the Town of Silver Plume. The avalanche brought trees, rock, soil and snow to the valley floor, knocked down overhead utility lines, blocked the I-70 frontage road, damaged the town’s water treatment plant (WTP), and dammed Clear Creek. The dam was breached using explosives before the plant’s electric pump motors were flooded. With damage to the WTP’s chlorine contact tank and building, Silver Plum...
West view of the 2003 sinkhole showing proximity to campus buildings. Sunlight Ski Area is on the left horizon. Roaring Fork River valley is in left middle background below the ski area and in front of first row of ridges. Photo credit: Jon White for the CGS.|South close-up view of sinkhole wall showing uniform silt sediments derived from windblown deposits (loess). CMC maintenance staff had started to fill the sinkhole with broken road-pavement waste. Photo credit: Jon White for the CGS.|Sample of the loess from the wall of the sinkhole. Photo credit: Jon White for the CGS.|The sinkhole site Geology, Hazards February 4, 2003 Case Study: Colorado Mountain College, Spring Valley In early February of 2003, a 24-foot-wide (7.5 m) sinkhole spontaneously opened on a soccer field at the Colorado Mountain College (CMC) – Spring Valley campus, about 10 miles (16 km) southeast of Glenwood Springs in Garfield County. The CMC physical plant maintenance staff back-filled the hole with road pavement…
SP-43 A Guide to Swelling Soils for Colorado Homebuyers and Homeowners Hazards September 26, 2001 Swelling Soil Publication Wins Another National Award CGS Special Publication 43, SP-43 A Guide to Swelling Soils for Colorado Homebuyers and Homeowners, by Dave Noe, William “Pat” Rogers, and Candace Jochim, is the winner of the 2001 Edward B. Burwell, Jr. Award by the Geological…
The Purgatoire River dinosaur trackway at twilight Geology October 1, 2000 A Dash with Dinosaurs In the next months, we will be sharing some unpublished field trip guides that we have made over the years. The occasion for this one was “Earth Science Week” back in 2000, an annual event initiated by the…
A precarious rock above Manitou Springs started to move in 1995 after a period of wet weather. As an emergency measure Hazards June 20, 1995 Case Study: Rockfall – Manitou Springs [ED: This report from 1995 was written by Jon White, (Senior Engineering Geologist, Emeritus). It looks at a specific rockfall situation in the central Front Range town. ] Manitou Springs occupies a narrow valley where Fountain Creek emerges from the foothills northeast of Pikes Peak and west of Colorado Springs. The valley slopes are composed of interbedded resistant sandstone and conglomerates (i.e., gravelly sandstone), and weaker mudstones and shale. The outc...
Isoseismal map for the earthquake north-east of Denver - 9 August 1967 - MMI VII. (detail) Geology, Hazards August 9, 1967 Case Study: Denver – August 9, 1967 Major magnitude 5.3 earthquake shock in Denver One of the strongest and most economically damaging earthquakes to affect the Denver area in the 1960s occurred on August 9, 1967 around 6:30 AM, awakening and frightening thousands of people. This magnitude 5.3 earthquake, centered near Commerce…